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UIElement.ManipulationDelta Event

Occurs when the input device changes position during a manipulation.

Namespace:  System.Windows
Assembly:  PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public event EventHandler<ManipulationDeltaEventArgs> ManipulationDelta
<object ManipulationDelta="EventHandler<ManipulationDeltaEventArgs>" .../>

The ManipulationDelta event occurs multiple times when the user drags fingers over the screen during a manipulation and again when inertia occurs. You can use the IsInertial property to check whether the event is occurring during inertia.

The element on with ManipulationDelta event occurs is not affected in any way when the event occurs. You must provide the logic to the element that is to be manipulated. The CumulativeManipulation and DeltaManipulation properties, which are of type ManipulationDelta, contain data about how the position of the manipulations change and interpreted as moving, resizing, or rotating an object. You apply that information to the element that is to be manipulated.

For more information about manipulations, see the Input Overview. For an example of an application that responds to manipulations, see Walkthrough: Creating Your First Touch Application.

The following example shows an event handler for the ManipulationDelta event. The example uses the DeltaManipulation property to move, resize, and rotate a Rectangle. The example also checks whether the ManipulationDelta event occurred during inertia and whether the rectangle is touching the edge of a window. If those cases are true, the application stops the manipulation to prevent the rectangle from leaving the visible area of the application. This example is part of a larger example in Walkthrough: Creating Your First Touch Application.

void Window_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{

    // Get the Rectangle and its RenderTransform matrix.
    Rectangle rectToMove = e.OriginalSource as Rectangle;
    Matrix rectsMatrix = ((MatrixTransform)rectToMove.RenderTransform).Matrix;

    // Rotate the Rectangle.
    rectsMatrix.RotateAt(e.DeltaManipulation.Rotation, 
                         e.ManipulationOrigin.X, 
                         e.ManipulationOrigin.Y);

    // Resize the Rectangle.  Keep it square 
    // so use only the X value of Scale.
    rectsMatrix.ScaleAt(e.DeltaManipulation.Scale.X, 
                        e.DeltaManipulation.Scale.X, 
                        e.ManipulationOrigin.X,
                        e.ManipulationOrigin.Y);

    // Move the Rectangle.
    rectsMatrix.Translate(e.DeltaManipulation.Translation.X,
                          e.DeltaManipulation.Translation.Y);

    // Apply the changes to the Rectangle.
    rectToMove.RenderTransform = new MatrixTransform(rectsMatrix);

    Rect containingRect =
        new Rect(((FrameworkElement)e.ManipulationContainer).RenderSize);

    Rect shapeBounds =
        rectToMove.RenderTransform.TransformBounds(
            new Rect(rectToMove.RenderSize));

    // Check if the rectangle is completely in the window.
    // If it is not and intertia is occuring, stop the manipulation.
    if (e.IsInertial && !containingRect.Contains(shapeBounds))
    {
        e.Complete();
    }


    e.Handled = true;
}

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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